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NBME 21 Answers

Block 1/Question#1
A 24-year-old woman with sickle cell disease comes to the ...
Serum parvovirus B19 IgM antibody test

Block 1/Question#2
A 6-month-old girl is brought to the physician because her ...
GM2

Block 1/Question#3
An investigator is studying the efficacy of distinct vaccine ...
Flagellin

Block 1/Question#4
A 67-year-old man comes to the emergency department because ...
Translation

Block 1/Question#5
A 45-year-old woman is brought to the emergency department 45 ...
Absorption atelectasis

Block 1/Question#6
A normal-appearing 17-year-old girl has never had a menstrual ...
Androgen insensitivity syndrome

Block 1/Question#7
A 30-year-old primigravid woman at 22 weeks' gestation comes ...
Listeria monocytogenes

Block 1/Question#8
A 52-year-old woman is admitted to the hospital because of ...
Speak with the two gynecologists to attempt to coordinate care

Block 1/Question#9
A 53-year-old woman who underwent an operation for breast ...
Breast: antagonist; Uterus: partial agonist

Block 1/Question#10
A 34-year-old woman is brought to the emergency department 30 ...
Primary metabolic acidosis with increased anion gap

Block 1/Question#11
A 27-year-old primigravid woman at 34 weeks' gestation is ...
Schistocytes

Block 1/Question#12
A 25-year-old nulligravid woman comes to the physician ...
Endometrial hyperplasia

Block 1/Question#13
A 25-year-old man develops shortness of breath after moving ...
Decreased alveolar Po2

Block 1/Question#14
A 21-year-old man is brought to the emergency department 45 ...
Streptococcus pneumoniae

Block 1/Question#15
A 35-year-old man comes to the physician because of a 1-day ...
Increased vascular permeability

Block 1/Question#16
A 43-year-old man comes to the physician for a follow-up ...
Aortic

Block 1/Question#17
A 7-year-old girl is brought to a clinic in a developing ...
Methionine

Block 1/Question#18
A 61-year-old woman is brought to the physician by her ...
Donepezil

Block 1/Question#19
A 22-year-old man has had frequent episodes of cutaneous ...
C1 esterase inhibitor (binds activated C1r, C1s)

Block 1/Question#20
A 10-year-old girl develops fever, malaise, and loss of ...
Retrograde transport through nerves

Block 1/Question#21
A 40-year-old man with type 2 diabetes mellitus comes to the ...
Stimulation of the peroxisome proliferator-activated receptor γ

Block 1/Question#22
A 36-year-old man with AIDS elects to participate in a ...
Chemokine

Block 1/Question#23
A 59-year-old man comes to the physician because of a 3-month ...
Foci of keratinization

Block 1/Question#24
A 23-year-old man drinks alcohol heavily on a weekend. Which ...
Fatty change

Block 1/Question#25
A 28-year-old man is brought to the emergency department 30 ...
Dissecting aneurysm

Block 1/Question#26
A 62-year-old man who is a farmer comes to the physician ...
Actinic keratosis

Block 1/Question#27
A 60-year-old man is brought to the emergency department ...
Urethral disruption

Block 1/Question#28
A 47-year-old man is brought to the emergency department by ...
Mixed venous oxygen tension

Block 1/Question#29
A 34-year-old man comes to the physician because of a 2-week ...
Cluster headache

Block 1/Question#30
A newborn has female external genitalia and a 46,XY ...
Dihydrotestosterone

Block 1/Question#31
A 30-year-old woman comes to the office for a follow-up ...
Linoleic acid

Block 1/Question#32
A 50-year-old man has had progressive dyspnea on exertion ...
Usual interstitial pneumonitis

Block 1/Question#33
A 30-year-old man comes to the physician because of a ...
Varicella-zoster virus infection

Block 1/Question#34
A 30-year-old man develops urinary incontinence 2 weeks after ...
Pelvic nerves

Block 1/Question#35
A 7-year-old boy is brought to the physician by his mother ...
Increased blood lead

Block 1/Question#36
A 51-year-old woman comes to the physician because of a ...
Area labeled 'B' (Parietal cell)

Block 1/Question#37
A 35-year-old man with diabetic ketoacidosis has a decrease ...
Serum potassium concentration

Block 1/Question#38
A 47-year-old woman with aplastic anemia is being treated for ...
Amphotericin B

Block 1/Question#39
A 33-year-old woman comes to the physician because of fever, ...
Genital herpes

Block 1/Question#40
A physician prescribes a recently marketed drug for 20 ...
Phase 4

Block 1/Question#41
A 35-year-old woman comes to the physician because of a 2-day ...
Uroporphyrinogen decarboxylase

Block 1/Question#42
A 36-year-old woman undergoes a total hysterectomy and ...
Hyperplasia

Block 1/Question#43
A 52-year-old man is brought to the emergency department 30 ...
Histamine

Block 1/Question#44
A test has been developed to screen for human papillomavirus ...
Predictive value of a positive test

Block 1/Question#45
An 18-year-old man comes to the physician because of a 2-week ...
Pyruvate kinase

Block 1/Question#46
A 66-year-old man is brought to the emergency department ...
Lipopolysaccharide stimulation of toll-like receptor

Block 1/Question#47
A 26-year-old woman (III-2) comes to the physician for ...
50% in females but near 0 in males

Block 1/Question#48
A 44-year-old man is admitted to the hospital because of ...
Increasing cGMP

Block 1/Question#49
An 80-year-old woman comes to the emergency department ...
Hydrochlorothiazide

Block 1/Question#50
A photograph is shown of a myelin-stained cross section of a ...
Loss of sensation to vibration over both feet

Block 2/Question#1
A 27-year-old man comes to the physician for an examination ...
Schizoid

Block 2/Question#2
A 4-year-old girl is conscious but unable to breathe ...
Pseudocholinesterase deficiency

Block 2/Question#3
A 17-year-old boy returns to the locker room after football ...
Apocrine

Block 2/Question#4
An 18-year-old woman comes to the office because of a 2-week ...
Extensor carpi radialis brevis

Block 2/Question#5
A 2-week-old male newborn has a patent ductus arteriosus. ...
Higher than normal left ventricular cardiac output

Block 2/Question#6
A 38-year-old woman comes to the physician because of a ...
Serum calcium concentration

Block 2/Question#7
A 50-year-old man with rheumatoid arthritis comes to the ...
Anemia of chronic disease

Block 2/Question#8
A 55-year-old man is diagnosed with renal artery stenosis. ...
Cortex

Block 2/Question#9
A 40-year-old man is brought to the emergency department 45 ...
Metabolic acidosis and respiratory acidosis

Block 2/Question#10
A 42-year-old woman comes to the physician because of a ...
Rosacea

Block 2/Question#11
A 22-year-old woman, gravida 1, para 1, is brought to the ...
Internal iliac

Block 2/Question#12
A 66-year-old woman comes to the physician because of fever, ...
Diverticulitis

Block 2/Question#13
A 53-year-old woman with gastroesophageal reflux disease ...
Omeprazole

Block 2/Question#14
A 30-year-old woman comes to the office because she is ...
Abnormal brain development

Block 2/Question#15
A 48-year-old man is brought to the emergency department ...
Splenic and left renal

Block 2/Question#16
A 34-year-old woman comes to the physician because of a ...
Atrioventricular bundle

Block 2/Question#17
Scientists have identified the flawed gene that causes about ...
Mismatch repair

Block 2/Question#18
A 34-year-old woman comes to the physician because she has ...
“I’m concerned about how bad you’ve been feeling lately. Have you had any thoughts about death or wanting to be dead?”

Block 2/Question#19
A 3-year-old boy who recently immigrated to the USA is ...
Increased proportions of osteoid

Block 2/Question#20
A 14-year-old girl is brought to the physician by her mother ...
Trichotillomania

Block 2/Question#21
A 35-year-old woman undergoes flexible nasopharyngoscopy ...
Superior to the superior concha

Block 2/Question#22
A 33-year-old woman, gravida 4, para 4, is admitted to the ...
Transfusion-related acute lung injury

Block 2/Question#23
A 4-year-old boy with chronic granulomatous disease is ...
Macrophages producing interleukin-1 (IL-1)

Block 2/Question#24
A 65-year-old man dies in a motor vehicle collision. A ...
Squamous cell carcinoma

Block 2/Question#25
A 54-year-old man comes to the physician for a routine health ...
Area labeled 'F' (Efferent arteriole)

Block 2/Question#26
A healthy 32-year-old woman at 35 weeks' gestation is ...
Birth canal reflex

Block 2/Question#27
A 47-year-old woman with psoriasis comes to the physician for ...
“Most people find it difficult to stick to a routine. How did you do?”

Block 2/Question#28
A 64-year-old woman with type 2 diabetes mellitus and ...
Gemfibrozil

Block 2/Question#29
A healthy 25-year-old man is participating in a study of ...
Alanine

Block 2/Question#30
A 44-year-old man comes to the physician because of ...
Leukotriene C4: increased;
Arachidonic acid: increased;
Prostaglandin H2: decreased;
Prostaglandin E2: decreased


Block 2/Question#31
A 37-year-old man is brought to the emergency department 45 ...
Intercostal

Block 2/Question#32
A 17-year-old boy has the acute onset of lethargy, sore ...
Lymphocytes

Block 2/Question#33
A 68-year-old man comes to the physician because of a 1-month ...
Libido: normal; Nocturnal erections: normal

Block 2/Question#34
A 28-year-old man is brought to the emergency department ...
Inferior rectus and inferior oblique

Block 2/Question#35
A 4-month-old female infant is brought to the emergency ...
Hyponatremia

Block 2/Question#36
An investigator is conducting a study of antiretroviral ...
Enfuvirtide

Block 2/Question#37
A 17-year-old boy is evaluated for constitutional delay in ...
Craniopharyngioma

Block 2/Question#38
A 63-year-old man with bladder cancer starts treatment with ...
Tubulin polymerization stabilization

Block 2/Question#39
A 64-year-old man with bronchospastic pulmonary disease ...
Enhanced action of the agonist at β-adrenergic receptors

Block 2/Question#40
Acetaminophen and nonsteroidal antiinflammatory agents reduce ...
Prostaglandin E2

Block 2/Question#41
A 75-year-old woman has the sudden onset of Horner syndrome ...
Posterior inferior cerebellar

Block 2/Question#42
A 26-year-old man with HIV infection comes to the physician ...
Penicillin

Block 2/Question#43
A 78-year-old woman is brought to the emergency department by ...
Embolectomy

Block 2/Question#44
A 75-year-old man has the sudden onset of partial loss of ...
Parietal lobe, left

Block 2/Question#45
A 3-year-old boy is brought to the emergency department ...
Synthesis of factor X (Stuart factor)

Block 2/Question#46
An 8-year-old girl is brought to the physician for a ...
“Your daughter’s development is normal.”

Block 2/Question#47
A 55-year-old woman comes to the physician because of a ...
Increased parathyroid hormone

Block 2/Question#48
A 75-year-old man has fever, back pain, and pain on ...
Enterococcus faecalis

Block 2/Question#49
A 6-year-old girl is brought to the physician by her mother ...
Poxvirus

Block 2/Question#50
A 65-year-old woman comes to the emergency department because ...
Lung and common carotid artery

Block 3/Question#1
A 30-year-old woman develops dimness of vision
Ethambutol

Block 3/Question#2
A 40-year-old man with interstitial pulmonary fibrosis has a ...
Increased radial traction on airways

Block 3/Question#3
A 55-year-old African American man with hypertension is asked ...
Tell the patient that he can change his mind about participating

Block 3/Question#4
A clinical trial is conducted to compare the efficacy of a ...
Surgical procedure group: 400; Medical management group: 400

Block 3/Question#5
A 70-year-old woman is found to have persistent fever despite ...
Candida albicans

Block 3/Question#6
A 40-year-old African American woman comes to the physician ...
1,25-Dihydroxycholecalciferol

Block 3/Question#7
A 65-year-old man comes to the physician because of a 1-month ...
DNA fragmentation

Block 3/Question#8
A 55-year-old woman is brought to the emergency department by ...
Mammillary bodies

Block 3/Question#9
A 75-year-old woman is brought to the emergency department ...
Shrunken eosinophilic (red) neurons

Block 3/Question#10
A 30-year-old man has had intermittent severe lower abdominal ...
Cysteine

Block 3/Question#11
A 50-year-old man is found dead in bed at home. His family ...
Arrhythmia

Block 3/Question#12
A 55-year-old man with hypertension comes to the physician ...
Left renal artery atherosclerosis

Block 3/Question#13
A 40-year-old woman comes to the physician for an initial ...
Antagonizes VLDL-cholesterol secretion

Block 3/Question#14
A 35-year-old man is brought to the emergency department ...
Activation of adenylyl cyclase

Block 3/Question#15
A 47-year-old man has jaundice. Laboratory findings include ...
Obstruction of the bile duct

Block 3/Question#16
A 16-year-old boy is brought to the physician because of a ...
Exercise-induced asthma

Block 3/Question#17
A 66-year-old woman with pancreatic cancer comes to the ...
Short gastric

Block 3/Question#18
An 83-year-old man comes to the physician because of a 3-day ...
Bullous pemphigoid antigen

Block 3/Question#19
A 25-year-old woman develops increasing shortness of breath ...
Four-chamber dilation

Block 3/Question#20
A 68-year-old woman has had a fever and shortness of breath ...
Reactive granulocytosis

Block 3/Question#21
A screening program is instituted for detection of vaginal ...
10%

Block 3/Question#22
A 9-year-old boy has mild mental retardation and a 4-year ...
Rhabdomyoma

Block 3/Question#23
A 43-year-old woman dies after a 10-year illness ...
Area labeled ‘C’ (Caudate nucleus)

Block 3/Question#24
Diastolic blood pressures are obtained in two groups of 100 ...
Median of group Y: higher; Mode of group Y: higher

Block 3/Question#25
A 32-year-old woman comes to the physician because her sister ...
Dysplastic nevi

Block 3/Question#26
A 19-year-old woman comes to the office because of a 1-month ...
Descending colon

Block 3/Question#27
A 55-year-old woman with a benign nodule in the left lobe of ...
External carotid

Block 3/Question#28
A 1-year-old girl is admitted to the hospital because of a ...
Disruption of the secondary structure of collagen molecules

Block 3/Question#29
A 34-year-old man is evaluated after becoming light-headed ...
Number of impulses from carotid baroreceptor: decreased;
Sympathetic efferent activity: increased;
Parasympathetic efferent activity: decreased


Block 3/Question#30
A 41-year-old man comes to the physician because of a 6-week ...
Abduction of the upper extremity

Block 3/Question#31
A 28-year-old woman at 18 weeks' gestation has palpitations. ...
Free T4

Block 3/Question#32
A 72-year-old man comes to the physician because of a 2-week ...
Bleomycin

Block 3/Question#33
Left radial arterial and venous blood samples are drawn from ...
HCO3 transported in the plasma

Block 3/Question#34
A 39-year-old woman with rheumatoid arthritis develops ...
Membranous glomerulonephritis

Block 3/Question#35
A 63-year-old woman comes to the physician because of a 5-day ...
Increased resting cardiac output

Block 3/Question#36
Which of the following best explains why the use of an ...
Myeloma cells do not have membrane-bound surface immunoglobulin

Block 3/Question#37
A 5-year-old boy who has homocystinuria improves with ...
The line on the graph labeled ‘B’

Block 3/Question#38
A 28-year-old man develops a temperature of 39.9°C (103.8°F) ...
Granulocyte colony-stimulating factor

Block 3/Question#39
A 74-year-old woman with mild dementia is admitted to the ...
Inability to understand the severity and prognosis of her medical condition

Block 3/Question#40
A 65-year-old woman undergoes surgical repair of an aneurysm ...
Area labeled ‘A’ (Cranial nerve 3)

Block 3/Question#41
A 75-year-old woman comes to the physician's office because ...
Major depressive disorder

Block 3/Question#42
A 27-year-old primigravid woman at 39 weeks' gestation is ...
Shoulder dystocia

Block 3/Question#43
An undernourished 70-year-old man has fever, night sweats, ...
Interferon-γ

Block 3/Question#44
A 23-year-old woman develops persistent sneezing each year in ...
Stabilization of mast cell membranes

Block 3/Question#45
A 28-year-old man comes to the physician for evaluation of ...
Fructose

Block 3/Question#46
A 38-year-old woman comes to the physician because of a ...
Patent foramen ovale

Block 3/Question#47
A 48-year-old man comes to the physician because of ...
Increased intestinal iron absorption

Block 3/Question#48
A 29-year-old woman comes to the physician because of a ...
Baclofen

Block 3/Question#49
The gene that codes for a protein normally found in the ...
Deletion of a hydrophobic amino acid sequence from the N terminus

Block 3/Question#50
A 32-year-old woman comes to the emergency department because ...
Arthropod vector

Block 4/Question#1
A 50-year-old woman has azotemia. Renal ultrasonography shows ...
Uterine cervix

Block 4/Question#2
A 23-year-old woman comes to the student health center ...
Obliterative endarteritis with lymphocytes and plasma cells

Block 4/Question#3
A study was performed that evaluated the relationship between ...
Odds ratio

Block 4/Question#4
The FOXO transcription factor responds to insulin signaling ...
Nuclear/cytoplasmic shuttling: yes;
Serine phosphorylation: yes
Ubiquitin-mediated proteolysis: no


Block 4/Question#5
An 11-year-old boy has had persistent pain in his right knee ...
Lung

Block 4/Question#6
A 55-year-old man comes to the physician because of a 2-month ...
Cortisol

Block 4/Question#7
A 14-year-old boy is brought to the physician by his mother ...
Inhaled glue

Block 4/Question#8
A 70-year-old woman has had recurrent pneumonia, fatigue, and ...
Euthyroid sick syndrome

Block 4/Question#9
A 60-year-old woman with psoriasis comes to the physician ...
Porphyria cutanea tarda

Block 4/Question#10
A 64-year-old man is evaluated for cough, dyspnea, and chest ...
Hyponatremia

Block 4/Question#11
A study is conducted on patients with asthma to compare a new ...
If the treatment really changes the mean asthma score by 0.4, there is an 80% chance that a study of this size will find a p-value < 0.05

Block 4/Question#12
A 24-year-old man with a history of drug abuse has nausea, ...
Heroin

Block 4/Question#13
A 4-month-old boy is diagnosed with a rare autosomal ...
Dilated rough endoplasmic reticulum

Block 4/Question#14
A 25-year-old woman has a 3-week history of bleeding gums ...
Autoantibodies against platelet glycoproteins

Block 4/Question#15
A 5-year-old boy is brought to the physician for a well-child ...
Lack of choroidal pigment deposition in the macula

Block 4/Question#16
A 40-year-old woman who had pneumonia due to Streptococcus ...
Surfactant

Block 4/Question#17
A 48-year old man is referred for evaluation of possible ...
Increase in width

Block 4/Question#18
A previously healthy 4-week-old male newborn is brought to ...
Pyloric stenosis

Block 4/Question#19
A 45-year-old woman comes to the emergency department because ...
Hepatopancreatic ampulla

Block 4/Question#20
A 7-month-old boy is brought to the physician 2 days after ...
46,XY

Block 4/Question#21
A 47-year-old man is treated with colchicine for acute gouty ...
Tubulin polymerization

Block 4/Question#22
A 57-year-old woman is brought to the emergency department ...
Ninth

Block 4/Question#23
An investigator is studying the regulation of pulmonary ...
Intravenous infusion of 0.9% saline for 5 minutes

Block 4/Question#24
A 56-year-old man undergoes a renal transplant. Five minutes ...
IgG plus complement

Block 4/Question#25
An 80-year-old woman cannot concentrate her urine above 450 ...
2.0

Block 4/Question#26
The immunosuppressive agent cyclosporin A (CsA) is a potent ...
Interleukin-2 (IL-2) gene transcription

Block 4/Question#27
A 65-year-old woman is being treated in the hospital for ...
“The two of you seem to have a very important relationship. Of course you may stay together.”

Block 4/Question#28
A 56-year-old man undergoes surgical resection of the ...
Release of cholecystokinin

Block 4/Question#29
A 22-year-old man comes to the physician because of a 2-month ...
Formation of destructive free radicals

Block 4/Question#30
A 5-year-old boy is admitted to the hospital because of ...
ApoC-II

Block 4/Question#31
A 48-year-old woman comes to the physician because of a ...
Paracrine stimulation of osteoclasts by osteoblasts

Block 4/Question#32
A 19-year-old college student says he hears voices." He was ...
Risperidone

Block 4/Question#33
A female newborn delivered at 26 weeks' gestation is found to ...
Retina

Block 4/Question#34
A healthy 8-year-old boy is brought to the physician by his ...
Stimulation of the release of biogenic amine neurotransmitters

Block 4/Question#35
A 50-year-old woman is admitted to the hospital because of a ...
Didanosine (ddI)

Block 4/Question#36
A 45-year-old man comes to the physician because of ...
Chondrosarcoma

Block 4/Question#37
A 66-year-old right-handed woman develops the acute onset of ...
Area labeled 'B' (Internal capsule)

Block 4/Question#38
A 62-year-old woman is brought to the physician by her ...
Instruct the patient to keep notes and lists to help her memory

Block 4/Question#39
A 46-year-old man comes to the physician because of a 2-month ...
1/15

Block 4/Question#40
A study is conducted to assess the normal mean serum urea ...
500 Men from a list of patients scheduled to be examined by a urologist

Block 4/Question#41
A 66-year-old man with stage IV colon cancer comes to the ...
Loperamide

Block 4/Question#42
A 20-year-old primigravid woman at 12 weeks' gestation comes ...
Multifactorial

Block 4/Question#43
A 4-year-old boy falls and lacerates his lower leg to the ...
Formation of fibrin clot

Block 4/Question#44
A 28-year-old woman with chronic renal failure (creatinine ...
Furosemide

Block 4/Question#45
During an experiment, an investigator observes that glutamate ...
NMDA receptors are blocked by Mg2+ at the resting membrane potential

Block 4/Question#46
A 14-year-old girl is brought to the physician for a ...
TP53

Block 4/Question#47
While lifting weights, a 24-year-old man develops a painful ...
Strangulation

Block 4/Question#48
A 75-year-old man with dementia, Alzheimer type, is brought ...
Encourage the family to come to a consensus based on their perception of the patient's wishes

Block 4/Question#49
A 76-year-old man comes to the physician because of a 2-week ...
Left thalamus

Block 4/Question#50
A 19-year-old woman is brought to the emergency department 30 ...
Scaphoid

Recent comments ...

... jo made a comment on nbme21/block1/q#1 (A 24-year-old woman with sickle cell disease comes...)
 +5  upvote downvote
submitted by jo(7)

Parvo infects RBC precursors in the marrow which can cause aplastic crisis in sickle cell patients.

jo  Infection of precursors halt RBC maturation which leads to giant pronormoblasts with intranuclear viral inclusions in the periphery (UWorld)
... temmy made a comment on nbme21/block1/q#1 (A 24-year-old woman with sickle cell disease comes...)
 +2  upvote downvote
submitted by temmy(23)

Healthy people who get sick with parvovirus may have a subclinical illness with athralgias as the only symptom. But sickle cell patients and patients with decreases hematopoiesis will develop[ bone marrow failure because the virus affect the hematopoietic stem cells leading to aplastic crises and inability for the bone marrow to adequately compensate hence the low reticulocyte count. parvovirus causes..slapped cheeks in kids hydrops fetalis in fetus, aplastic crises in sickle cell and arthralgias in other patients.

henoch280  thanks. very helpful
... kjfhewiufh made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 -1  upvote downvote
submitted by kjfhewiufh(-3)

[special]

... kjfhewiufh made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 -1  upvote downvote
submitted by kjfhewiufh(-3)

[special]

... kjfhewiufh made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 -1  upvote downvote
submitted by kjfhewiufh(-3)

[special]

... mcl made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +2  upvote downvote
submitted by mcl(186)

Patient most likely has Tay-Sachs disease. This figure nicely shows the biochemical pathway. Recall that both Tay-Sachs and Neimann Pick disease present with a cherry red spot on fundoscopy, but Tay Sachs lacks the hepatosplenomegaly seen in NP.

hungrybox  Man this is such a nice figure except it doesn't have Krabbe disease :(
mcl  Here's another one with Krabbe! :) https://epomedicine.com/wp-content/uploads/2017/01/lysosomal-storage-diseases-enzyme-defects.jpg
hungrybox  thank u
kjfhewiufh  [special]
... usmleuser007 made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +4  upvote downvote
submitted by usmleuser007(97)

1) Very important to note that Tay-Sachs disease has more sensitive startle (moro) reflex in neonates with increased head circumference.

2) Fabry disease = tend to have audio-visual defects w/o liver involvement

3) Niemann-pick disease = anemia & hypotonia with areflexia

... seagull made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +7  upvote downvote
submitted by seagull(387)

! I hate these with a burning F***ing passion. Thumbs up if you agree

mcl  Amen brother
praderwilli  Every morning: "I think i'll go over glycogen storage diseases, lysosomal storage diseases, and dyslipidemias after questions this afternoon." Every afternoon: Nah
mcl  oh my god are you me
praderwilli  I recently found a program called Pixorize. It's pretty much Sketchy for biochem. Wish I discovered it sooner cuz it has helped for a lot of the painful things like this!
tentorium  [special]
tentorium  [special]
tentorium  [special]
drhello  hello
burak  Cherry red spot basically means niemann-pick or tay sachs. Two differences between is: 1- No HSM in Tay Sachs, HSM in niemann-pick. 2- Both of them has muscle weakness but there is hyperreflexia in Tay Sachs, but areflexia in niemann pick disease. In stem cell HSM is not described and hyperreflexia noted.
... awabnaeim made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +0  upvote downvote
submitted by awabnaeim(0)

I think the exaggerated startle in tay sachs is actually due to the hyperacusis, this is mentioned in first aid

... burak made a comment on nbme21/block1/q#2 (A 6-month-old girl is brought to the physician...)
 +0  upvote downvote
submitted by burak(4)

Cherry red spot basically means niemann-pick or tay sachs. Two differences between is: 1- No HSM in Tay Sachs, HSM in niemann-pick. 2- Both of them has muscle weakness but there is hyperreflexia in Tay Sachs, but areflexia in niemann pick disease. In stem cell HSM is not described and hyperreflexia noted.

burak  i mean, hyperacusis+hyperreflexia+sensitive startle
... cantaloupe5 made a comment on nbme21/block1/q#3 (An investigator is studying the efficacy of distinct...)
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submitted by cantaloupe5(32)

Capsular polysaccharide vaccines are often conjugated to proteins to improve immunogenicity. Flagellin is the only answer choice that's a protein.

... wasabilateral made a comment on nbme21/block1/q#3 (An investigator is studying the efficacy of distinct...)
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submitted by wasabilateral(15)

I think they want you to think about how conjugate vaccine is made: polysaccharide + protein fragment (to induce T dependent immune response). Only flagellin is a protein (or at least sounds like one) in the option list.

vi_capsule  Flagellum is protein. Pilli/Fimbriae - GLycoprotein
... enbeemee made a comment on nbme21/block1/q#3 (An investigator is studying the efficacy of distinct...)
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submitted by enbeemee(4)

i get why it's flagellin, but is the specific reason that LPS is wrong is because it's just not how the vaccine is made? LPS would also elicit an immune reaction, right?

nor16  Lipid A of LPS can be sensed by CD14 of macrophages causing shock, its not a protein, so no immune reaction as in vaccination (humoral, IgG class switch via Th2 and B Cells).
eclipse  actually they do use LPS as adjuvant in vaccines
eclipse  actually they do use LPS as adjuvant in vaccines
hyperfukus  TLRs recognize common motifs called pathogen-associated molecular pattern (PAMP) in bacteria, fungi, viruses, and other pathogens. TLR signaling in the modulation of innate immunity + adaptive immunity against pathogens, TLR agonists: CpG-DNA, flagellin, and lipid became essential candidates of effective+safe vaccine adjuvants. TLR agonists improve the efficacy of vaccine, reducing TCR-based selection thresholds and enhancing the magnitude and quality of memory T-cell response.
hyperfukus  some extra info in case they ask another annoying q
... haliburton made a comment on nbme21/block1/q#4 (A 67-year-old man comes to the emergency department...)
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submitted by haliburton(76)

EF2 is translational elogation factor 2, which is necessary for protein synthesis.

sympathetikey  I. Am. So. DUMB.
nala_ula  same :(
... haliburton made a comment on nbme21/block1/q#5 (A 45-year-old woman is brought to the emergency...)
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submitted by haliburton(76)

wikipedia (apologies): The atmosphere is composed of 78% nitrogen and 21% oxygen. Since oxygen is exchanged at the alveoli-capillary membrane, nitrogen is a major component for the alveoli's state of inflation. If a large volume of nitrogen in the lungs is replaced with oxygen, the oxygen may subsequently be absorbed into the blood, reducing the volume of the alveoli, resulting in a form of alveolar collapse known as absorption atelectasis.

I chose cardiogenic edema, but I believe this is incorrect because there is no heart failure risk at this time, so the purpose of the PEEP is certainly not to push out fluid.

bighead478  doesn't there have to be an airway obstruction (mucus, foreign object etc.) in order for this to happen? 100% O2 without any airway obstruction should not cause absorption atelectasis, right?
iloveallpotatoes  And Tension Pneumothorax is wrong bc PEEP would furthur exacerbate that.
hyperfukus  @iloveallpotatoes yea i realized that now after getting it wrong :(
... nosancuck made a comment on nbme21/block1/q#5 (A 45-year-old woman is brought to the emergency...)
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submitted by nosancuck(32)

Bruh let me tell you a lil secret

PEEP prevents Atelectasis AKA dat LUNG COLLAPSE

Dont be worryin about random words they puts in front of the HIGH YIELD ones

hungrybox  literally LOL'd lmao I love this
... nosancuck made a comment on nbme21/block1/q#6 (A normal-appearing 17-year-old girl has never had a...)
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submitted by nosancuck(32)

Yo dis B got NO INTERNAL FEMALE ORGANS

Why dat!???

We be lookin at someone with an SRY from dere Y chromie! Dey be a Y chromie Homie so they be makin some Testis Determinin Factor which I be sure makes some nice lil ANTI MULLERIAN FACTOR so dey aint got that Female Internal Tract u know what i be sayin

And since wimminz is da DEFAULT they stil be gettin dose pussy lips and breastes

meningitis  The above explanation is correct (disregarding the hard to read and unprofessional dialect) but just in case anyone was wondering: chromatin-negative= Just a quick way of knowing it was a boy. The term applies to the nuclei of cells in normal males as well as those in individuals with certain chromosomal abnormalities
yotsubato  Turner syndrome patients are also chromatin negative as well though....
sympathetikey  I didn't know a complication post-meningitis was lack of humor.
sympathetikey  Ah, didn't read the last line. Yeah, that is taking it a bit far
niboonsh  yall are haters. this is the first explanation that has ever made sense to me
arkmoses  https://www.youtube.com/watch?v=yuXL-3eoB-o&t=77s Interesting syndrome watching this helped me to put it into real life perspective, interesting points they have no pubic hair/body hair, they apparently also dont smell, and breast size is usually increased...
whoissaad  How does chormatin-negative indicate a normal cell? Isn't chormatin just condensed DNA?
cienfuegos  According to this paper most individuals with Turner Syndrome are chromatin negative: "One of the initial laboratory procedures used to confirm or rule out this diagnosis involves a sex chromatin determination from a buccal smear. Cells from the lining of the mouth are stained for the presence or absence of X-chromatin or Barr bodies, which represent a portion of an inactivated X chromosome. The typical Turner’s syndrome patient, who has 45 chromosomes and only one sex chromosome (an X), has no Barr bodies and is, therefore, X-chromatin negative. This abnormal X-chromatin negative finding in the majority of Turner’s syndrome females is similar to the result found in a normal male, who also has only one X chromosome, and differs from the X-chromatin positive condition observed in the normal female, who has two X chromosomes. Occasionally, the patient with features of Turner’s syndrome is found to be X-chromatin positive." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6233891/
hyperfukus  i really hate haters this is awesome!
... nerdy nik made a comment on nbme21/block1/q#6 (A normal-appearing 17-year-old girl has never had a...)
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submitted by nerdy nik(2)

Turner syndrome-> The girl would have a uterus and streak ovaries.

... ergogenic22 made a comment on nbme21/block1/q#6 (A normal-appearing 17-year-old girl has never had a...)
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submitted by ergogenic22(38)

chromatin negative = no barr bodies = person with XY genotype or XO because anytime you have more than one X chromosome you have a barr body (chromatin positive)

... hyperfukus made a comment on nbme21/block1/q#6 (A normal-appearing 17-year-old girl has never had a...)
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submitted by hyperfukus(7)

Also another key is it says normal appearing girl one of the things about the AIS is that they do get secondary sexual characteristics...turner girls don't look normal they'd be short and stubby no boobs fat neck etc

... soph made a comment on nbme21/block1/q#6 (A normal-appearing 17-year-old girl has never had a...)
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submitted by soph(12)

all the other options pt would have uterus, ovaries. turners they wouldnt look normal and they would have atrophic ovaries.

... g.liller@yahoo.com made a comment on nbme21/block1/q#7 (A 30-year-old primigravid woman at 22 weeks'...)
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submitted by g.liller@yahoo.com(12)

gram +, B hemolytic, tumbling motility, form rocket tails from actin polymerization which allow for movement, intracellular, grows in cold temps on milk, soft cheeses, ice cream, lunch meat.

increased incidence in pregnant women especially in 3rd trimester

... taway made a comment on nbme21/block1/q#8 (A 52-year-old woman is admitted to the hospital...)
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submitted by taway(7)

Does anybody understand why we are allowed to interfere with the clinical decisionmaking of two other specialists directly? Wouldn't that muddy the waters even more by adding our opinion? I don't see the underlying principle that explains the rationale in this answer.

jcrll  I think it's about adding our opinion and more about seeing what the situation is because a patient contacted you in distress. The others are about contacting management off hearsay; that could also "muddy the waters," I Is this question also addressing quaternary prevention?
meningitis  I agree with jcrll. My same thought process but then I changed it to psychiatric consultation in order to first attend the patient's distress and anxiety since it was hindering her decision making. Besides, the whole ordeal about her treatments and ineffectiveness was emotionally and physically exhausting her.
vi_capsule  Referral is NEVER a answer
tsl19  Going straight to the chair of the ethics committee without having spoken to the other physicians would be inappropriate because it would be jumping a bunch of steps in communication first - like jcrll said, you want to get the picture of what's going on from the other physicians first. Maybe the gynecologic oncologist isn't actually as opposed to palliative measures as the patient perceives him to be and thinks he's doing what the patient wants, etc. It could just be miscommunication, which you could help clear up without getting ethics involved ... better to start there.
... temmy made a comment on nbme21/block1/q#8 (A 52-year-old woman is admitted to the hospital...)
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submitted by temmy(23)

I agree with what has been said but also note that the patient called her internist to help her address the conflict between the two physicians which has gotten her worried. That is her desire. And from what i have gathered, where possible, the patients wishes should be met.

... pparalpha made a comment on nbme21/block1/q#9 (A 53-year-old woman who underwent an operation for...)
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submitted by pparalpha(14)

Tamoxifen

Mechanism: selective estrogen receptor modulator (SERM) that acts as an antagonist on the estrogen receptors of the breast and acts as an partial agonist on estrogen receptors in bone and uterus. Therefore, ↑ risk of endometrial cancer and ↑ Risk of uterine sarcoma

Uses: ER or PR positive tumors (breast)

... temmy made a comment on nbme21/block1/q#10 (A 34-year-old woman is brought to the emergency...)
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submitted by temmy(23)

please help according to winters equation the patient has a normal anion gap

ergogenic22  winter's formula is to look at the compensation to see if it is appropriate. PCO2 = 1.5[HCO3-] + 8 +/- 2 In this case, 1.5* 10 (Pt's bicarb) +8 +/-2 = 21 to 25 Pt's PO2 is 23, so compensation is appropriate. If PCO2 was below 21, it would be concomitant respiratory alkalosis
ergogenic22  in other words, winter's formula is not necessary for this question
the_sacramento_kings  lol unless you want to make sure its not A.
hello  @ergogenic22 Someone might use Winter's formula to rule out choice A.
maxillarythirdmolar  respiratory depression of alcohol should rule out "A"
... ergogenic22 made a comment on nbme21/block1/q#10 (A 34-year-old woman is brought to the emergency...)
 +2  upvote downvote
submitted by ergogenic22(38)

Na-(Cl-+HCO3-)=anion gap = 140-(105+10) = 25 mEq/L

normal range for anion gap is 8 to 16 mEq/L...Therefore, positive anion gap.

pH = 7.25, normal range 7.35-7.45... Therefore acidosis

Normal bicarbonate 22-28, questions shows bicarb of 10. Therefore metabolic acidosis

Additionally PCO2 normally 33-45 mm Hg, question shows PCO2 of 23 with normal PO2, therefore respiratory compensation

... hayayah made a comment on nbme21/block1/q#11 (A 27-year-old primigravid woman at 34 weeks'...)
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submitted by hayayah(377)

HELLP syndrome: Hemolysis Elevated Liver enzymes Low Platelets.

A manifestation of severe preeclampsia. Blood smear shows schistocytes. Can lead to DIC and hepatic subcapsular hematomas Ž rupture Ž severe hypotension.

... mcl made a comment on nbme21/block1/q#12 (A 25-year-old nulligravid woman comes to the...)
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submitted by mcl(186)

PCOS is associated with abnormal production of sex steroids, including dysfunction of estrogen production and progesterone. Chronically elevated levels of estrogen can cause endometrial hyperplasia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3917599/

meningitis  Why isnt it endometriosis? Could someone help me out on this?
meningitis  Sorry, I was confusing with higher risk for endometrial carcinoma.
vi_capsule  Estrogen is responsible for cyclical bleeding and pain associated with endometriosis hence progestin is a treatment modality. But estrogen isnt a risk factor for Endometriosis. Rather theres retrograde flow, metaplatic transformation etc theories are responsible for endometriosis.
sympathetikey  Tfw you get so thrown off by a picture that you don't read the question properly.
hyperfukus  @meningitis idk if u still care lol but always go back to endometriosis=ectopic endometrial tissue outside of the uterus so you can rule it out since increased estrogen would cause you to have worsened endometriosis or a thicker one but not directly...you can see the clumps of the follicles in the ovaries if you look super close so that along with the presentation takes you to PCOS and anytime you don't have a baby or stay in the proliferative phase(estrogen phase) you get endometrial proliferation-->hyperplasia--->ultimately carcinoma
... pparalpha made a comment on nbme21/block1/q#12 (A 25-year-old nulligravid woman comes to the...)
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submitted by pparalpha(14)

Complications of PCOS:

Cardiovascular events

Type 2 diabetes mellitus

Endometrial cancer=hyperplasia

Increased miscarriage rate

... haliburton made a comment on nbme21/block1/q#13 (A 25-year-old man develops shortness of breath after...)
 +1  upvote downvote
submitted by haliburton(76)

FA 2017: Chronic hypoxic pulmonary vasoconstriction results in pulmonary hypertension and RVH.

yotsubato  Yeah but in a chronic case this guy would produce more RBC and not be hypoxic anymore.
... alexb made a comment on nbme21/block1/q#13 (A 25-year-old man develops shortness of breath after...)
 +2  upvote downvote
submitted by alexb(11)

Hypoxic pulmonary vasoconstriction (HPV), also known as the Euler-Liljestrand mechanism, is a physiological phenomenon in which small pulmonary arteries constrict in the presence of alveolar hypoxia (low oxygen levels).

While the maintenance of ventilation/perfusion ratio during regional obstruction of airflow is beneficial, HPV can be detrimental during global alveolar hypoxia which occurs with exposure to high altitude, where HPV causes a significant increase in total pulmonary vascular resistance, and pulmonary arterial pressure, potentially leading to pulmonary hypertension and pulmonary edema.

https://en.wikipedia.org/wiki/Hypoxic_pulmonary_vasoconstriction

... aesalmon made a comment on nbme21/block1/q#14 (A 21-year-old man is brought to the emergency...)
 +1  upvote downvote
submitted by aesalmon(34)

Splenectomy = more susceptible to encapsulated organisms

I put E. coli as its encapsulated but that wasn't the most right answer I guess?

pippylongstock  This question is asking about the ‘S’ of FA Mnemonic for S. Pneumonia “MOPS”. Strep pneumo is the most common cause of sepsis in adults.
emmy2k21  MOPS stands for meningitis, otitis, pneumonia, and SINUSITIS. It doesn't stand for sepsis. My guess as well is which is "more correct". It's about being able to identify encapsulated organisms and the spleen's role in immunity. Ha I chose E coli as well.
et-tu-bromocriptine  emmy2k21 is correct, the S is for sinusitis. I was between E.coli & Strep Pneumo, but then recalled Sketchy putting the sickle on the 'encapsulated' knight in the Strep Pneumo video; Strep Pneumo is more associated with infecting sickle cell "functionally asplenic" patients.
... sweetmed made a comment on nbme21/block1/q#15 (A 35-year-old man comes to the physician because of...)
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submitted by sweetmed(33)

The chemotactic factors produced by monocytes and mast cells and the local vasodilatation stimulates neutrophilic chemotaxis. Also, endothelial cells activation further aggravates the inflammatory response and migration of neutrophils. This leads to an influx of neutrophils locally.

refrence: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5512152/

... neonem made a comment on nbme21/block1/q#15 (A 35-year-old man comes to the physician because of...)
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submitted by neonem(243)

This is a case of acute gout. Monosodium urate crystals are taken up by neutrophils, leading to an acute inflammatory reaction. T-cells aren't really involved in gout (more rheumatoid arthritis).

hungrybox  Great explanation! So frustrating that I got this wrong, should have been easy.
temmy  the way i thought about it was how did the neutrophils get there? the answer is via increased vascular permeability
nor16  they, unfortunately, did not ask " how did neutrophils get there" but " whats the cause of the swelling " not to confuse with " what causes the swelling "
... mcl made a comment on nbme21/block1/q#16 (A 43-year-old man comes to the physician for a...)
hyperfukus  this link is great! they're still kind of close together :( its so hard to tell for me w/o reference of the others
hyperfukus  this link is great! they're still kind of close together :( its so hard to tell for me w/o reference of the others
... kentuckyfan made a comment on nbme21/block1/q#16 (A 43-year-old man comes to the physician for a...)
... usmleuser007 made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
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submitted by usmleuser007(97)

If you couldn't remember which were essential; then alternative would have been to realize that growing children need cells to divide. This requires DNA replication and translation. Of which the nucleic acid thyime is important. It requires a methyl transfer.

This is where methionine comes in. Methionine combines with ATP to form SAM (a methyl donor)

whossayin  That’s a legendary explanation. Thanks dude!
... mcl made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
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submitted by mcl(186)

Methionine is an essential amino acid. All others listed are not.

scalpelofthenorth  Pg 81 Tyrosine is listed as an essential AA. Should be tryptophan for those who got this wrong like me.
neonem  But tyrosine can come from phenylalanine, so it's not really essential right?
gh889  in FA2019, it is listed as Tryptophan, not Tyrosine. That was corrected.
usmleuser007  Note: Tyrosine is ONLY essential with PKU in children
niboonsh  bro FA2018 lists tyrosine as an essential AA. They played us.
... nosancuck made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
 +8  upvote downvote
submitted by nosancuck(32)

Yo dawg we all about PVT TIM HaLL

Phenylalanine, Valine, TryptoDANK, Threonine, Isoleucine, Methionine, Histidine, Leucine Lysine

meningitis  I don't understand what the question is asking... can someone please explain it to me? Patient doesnt eat protein, shes chubby. What does methionine have to do with this?
charcot_bouchard  Just basically asking which is essential amino acids.
usmleuser007  Essential amino acids (something i came up with) 1. "Three HAL fans will try meth" a. Threonine = Three b. Histidine; Arginine; Lysine = HAL c. Phenylalanine = fans d. Valine; Isoleucine; Leucine = will e. Tryptophan = try f. Methionine = meth
nala_ula  They're saying there is a lack of good quality protein -> slight nutritional deficiency. She may have acquired weight but it's not because of protein. So they're specifically asking what amino acid she might be missing due to her subpar diet. Since essential amino acids are those that the body cannot make itself, out off those listed, methionine is the essential amino acid. It's on page 81 of FA 2019.
nala_ula  correct me if I'm wrong please :)
hello  For anyone confused trying to follow @usmleuser007's comment -- slightly modified Essential amino acids mnemonic "Ah, Three fans will try meth" Ah = arginine, histidine Three = Threonine Fans (phans)= Phenylalanine Vil (Will -- German accent pronouncing English word 'will') = valine, isoleucine, leucine, lysine Try = tryptophan Meth = Methionine
... usmleuser007 made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
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submitted by usmleuser007(97)
1. "Three HAL fans will try meth"
    a. Threonine = Three 
    b. Histidine; Arginine; Lysine = HAL
    c. Phenylalanine = fans
    d. Valine; Isoleucine; Leucine = will
    e. Tryptophan = try
    f. Methionine = meth
pparalpha  Thanks! Good mnemonic
... usmleuser007 made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
 +3  upvote downvote
submitted by usmleuser007(97)

essential Amino acids (AA)

1) Adults require 9 (AA) = able to make argnine via urea cycle 2) Children require 10 (AA) = they are still developing 3) With PKU tyrosine becomes essential in both adults and children

... codyluvr95 made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
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submitted by codyluvr95(3)

B12 comes from protein and is a necessary cofactor for methionine synthase. Low B12 = low methionine.

... hello made a comment on nbme21/block1/q#17 (A 7-year-old girl is brought to a clinic in a...)
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submitted by hello(59)

For anyone confused trying to follow @usmleuser007's comment

Slightly modified

Essential amino acids mnemonic "Ah, Three fans will try meth"the

Ah = arginine, histidine

Three = Threonine

Fans (phans)= Phenylalanine

Vill (will -- German accent pronouncing English word "will") = valine, isoleucine, leucine, lysine

Try = tryptophan

Meth = Methionine

... ergogenic22 made a comment on nbme21/block1/q#18 (A 61-year-old woman is brought to the physician by...)
 +1  upvote downvote
submitted by ergogenic22(38)

elderly lady with slow, progressive memory loss, normal physical exam, no signs of depression, this is most likely Alzheimer disease.

AChE inhibitors are used for treatment because Alzheimer's is associated with low ACh. Also used are NMDA receptor antagonist (memantine)

... mcl made a comment on nbme21/block1/q#19 (A 22-year-old man has had frequent episodes of...)
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submitted by mcl(186)

Patient may have hereditary angioedema, which is associated with "recurrent attacks of intense, massive, localized subcutaneous edema involving the extremities, genitalia, face, or trunk, or submucosal edema of upper airway or bowels". The article goes on to say "C1-esterase inhibitor works directly on the complement and contact plasma cascades to reduce bradykinin release" which is also probably good to know.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666183/

notadoctor  Thought this was a trick question as C1 esterase deficiency also results in a decrease in C4. However, the second answer choice was not referring to C4 but to C4 binding protein, which I now know is different. I also didn't realize C1 esterase was technically a complement protein.
youssefa  Based on many sources hereditary angioedema does NOT cause a rash (urticaria) which is a main differentiating point between angioedema and allergy. This mislead me in this question. Any clarification?
ergogenic22  +1 on the above because uptodate states that c1 esterase inhibitor deficiency, both acquired and nonhereditary, are both non-urticarial, non-pruritic, and that is confirmed by the above linked article
sahusema  Question writer probably didn't know the difference between cutaneous urticaria and subcutaneous edema.
... est88 made a comment on nbme21/block1/q#20 (A 10-year-old girl develops fever, malaise, and loss...)
 +2  upvote downvote
submitted by est88(11)

Rabies Virus (rhabdoviridae)

Fever, encephalitis, drooling

... haliburton made a comment on nbme21/block1/q#20 (A 10-year-old girl develops fever, malaise, and loss...)
 +1  upvote downvote
submitted by haliburton(76)

Rabies attacks the nicotinic Acetylcholine receptor, and travels retrograde via dynein motors after binding AChR, according to FA.

... uslme123 made a comment on nbme21/block1/q#20 (A 10-year-old girl develops fever, malaise, and loss...)
 -4  upvote downvote
submitted by uslme123(6)

very stupid question. The virus was inhaled -- bats hang upside when they sleep and drool. So it spreads to the brain directly from the olfactory system via retrograde transport through nerves.

niboonsh  yea, aeresol transmission via bat poop in caves
... sgarzon15 made a comment on nbme21/block1/q#21 (A 40-year-old man with type 2 diabetes mellitus...)
 +2  upvote downvote
submitted by sgarzon15(2)

Thank you glitter zone of sketchy pharm. I shall never forget you

cr  why not C?. It´s not supose that it improve the efectivity of insulin?
cr  why not C?. It´s not supose that it improve the efectivity of insulin?
... cr made a comment on nbme21/block1/q#21 (A 40-year-old man with type 2 diabetes mellitus...)
 +0  upvote downvote
submitted by cr(1)

why not C?. It´s not supose that it improve the efectivity of insulin?

yb_26  thiazolidinediones (pioglitazone) increase insulin sensitivity (in muscles and liver) through activation of peroxisome proliferator-activated receptor-gamma (PPAR) I think they are asking about primarily mechanism of action, that's why it is E
cienfuegos  UW explanation regarding the genes upregulated 1. GLUT4: insulin responsive on adipocytes/skeletal increases G uptake 2. adiponectin: cytokine secreted by adipocytes increases # of insulin responsive adipocytes and stims FA oxidation 3. PPAR family also plays significant role in pathogenesis of metabolic syndrome
... hayayah made a comment on nbme21/block1/q#22 (A 36-year-old man with AIDS elects to participate in...)
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submitted by hayayah(377)

Cysteine-cysteine chemokine receptor 5 (CCR5) is a protein found on the surface of CD4 cells.

yotsubato  Note, this is NOT in FA
sbryant6  It is in UWorld.
... thechurchofbobbyhill made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
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submitted by thechurchofbobbyhill(1)

Hi- I don't have an explanation for this but I am also curious as to why this was the answer.

drdoom  via @hyoscyamine: FA pg.372. Squamous cell carcinoma occurs in the upper 2/3 of esophagus whereas adenocarcinoma occurs in the distal 1/3. Since this was in the mid esophagus, its squamous cell carcinoma. Key feature of squamous cell carcinoma is keratin pearls.
hyperfukus  idk why my dumbass didn't put foci of keratinization and pearls together lmao
... est88 made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
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submitted by est88(11)

I believe its Squamous cell carcinoma. Its centrally located, smoker, and its a hilar mass. Keratin pearls.

cry2mucheveryday  it is a case of esophageal carinoma not lung carcinoma.
... hyoscyamine made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
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submitted by hyoscyamine(19)

FA pg.372. Squamous cell carcinoma occurs in the upper 2/3 of esophagus whereas adenocarcinoma occurs in the distal 1/3. Since this was in the mid esophagus, its squamous cell carcinoma. Key feature of squamous cell carcinoma is keratin pearls.

... meningitis made a comment on nbme21/block1/q#23 (A 59-year-old man comes to the physician because of...)
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submitted by meningitis(136)

Squamous and Small cell carcinomas are Sentral (central) and often caused by Smoking

Hilar mass C arising from bronchus; Cavitation; Cigarettes; hyperCalcemia (produces PTHrP). Keratin pearls D and intercellular bridges.

pg 669 2019 FA

... vonhippelindau made a comment on nbme21/block1/q#24 (A 23-year-old man drinks alcohol heavily on a...)
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submitted by vonhippelindau(6)

It’s acute alcohol consumption so fatty change more likely. Cellular swelling indicates alcoholic hepatitis which requires chronic alcohol consumption (See FA 2019 pg 385). At least that’s the logic I used to pick fatty change.

seagull  Seems like fatty change would require more than 1 weekend. I choose swelling since it's reversible and seems like something with a quick onset.
nc1992  I think it's just a bad question. It should be "on weekends"
uslme123  https://webpath.med.utah.edu/LIVEHTML/LIVER145.html
uslme123  So his hepatocytes aren't dying ( ballon degeneration ) vs just damaged/increased FA synthesis due to increased NADH/citrate
sympathetikey  @seagull I agree!
et-tu-bromocriptine  It's not in pathoma, but I have it written in (so he or Dr. Ryan may have mentioned it) - Alcoholic hepatitis is generally seen in binge drinkers WITH A LONG HISTORY OF CONSUMPTION.
linwanrun1357  Do NOT think the answer of this question is right. Cell swelling make more sense!
... sweetmed made a comment on nbme21/block1/q#24 (A 23-year-old man drinks alcohol heavily on a...)
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Fatty Change in Liver [2/2 High NADH made by ADH and AldDH -> inhibits FA oxidation, impaired lipoprotein assembly and secretion-> FA accumulates.]

... usmleuser007 made a comment on nbme21/block1/q#24 (A 23-year-old man drinks alcohol heavily on a...)
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submitted by usmleuser007(97)

As per FA 1) fatty infiltration 2) cellular ballooning 3) eventual necrosis

hyperfukus  thanks u saved me time in looking that up :)
... youssefa made a comment on nbme21/block1/q#24 (A 23-year-old man drinks alcohol heavily on a...)
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submitted by youssefa(12)

Wouldn't acute alcohol consumption even in moderate amount cause reversible hepatic cellular injury characterized by cellular ballooning? It should be the right answer unless the question stem means "Weekends"

hello  No. The order of liver damage due to alcohol is: fatty changes --> cellular swelling (cellular balooning) --> necrosis. This Q stem states to the patient consumed large amount of alcohol on a weekend -- he has acutely drank a large amount of alcohol on one weekend --> this corresponds with fatty changes
et-tu-bromocriptine  It's not in pathoma, but I have it written in (so he or Dr. Ryan may have mentioned it) - Alcoholic hepatitis is generally seen in binge drinkers WITH A LONG HISTORY OF CONSUMPTION.
... neonem made a comment on nbme21/block1/q#25 (A 28-year-old man is brought to the emergency...)
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submitted by neonem(243)

Major risk factor for aortic dissection is hypertension, and in this case might be due to cocaine use, which causes marked hypertension. Dissections cause a tear in the tunica intima -- blood can flow backwards into the pericardium and cause tamponade. This manifests as crackles in the lung due to poor left ventricular function (filling/diastolic problem due to compression).

forerofore  there is another clue, the man has diminished pulses in just one arm, which means that the left subclavian artery must be involved somehow, and an aortic dissection would be the best answer explaining this.
temmy  please why is there where a diastolic mumur?
whoissaad  @temmy Aortic dissection especially near the root of aorta can lead to dilatation of the aortic valves, which can lead to Aortic regurgitation (diastoic murmur at left sternal border)
garibay92  Does anyone know why is this patient's tepmerature elevated?
ratadecalle  @garibay92, not important for this question I think but cocaine can cause malignant hyperthermia
... niboonsh made a comment on nbme21/block1/q#26 (A 62-year-old man who is a farmer comes to the...)
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submitted by niboonsh(62)

i think of this as ole farmer joe on his actinic farm picking karats (carrots) (actinic keratosis)

... sympathetikey made a comment on nbme21/block1/q#26 (A 62-year-old man who is a farmer comes to the...)
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submitted by sympathetikey(285)

The whole "picks at the lesion...causes some bleeding", made me think Psoriasis. Should have gone with Actinic Keratosis based on the patient history (lots of sun exposure).

Actinic Keratosis

Premalignant lesions caused by sun exposure. Small, rough, erythematous or brownish papules or plaques. Risk of squamous cell carcinoma is proportional to degree of epithelial dysplasia.

thisisfine   Same - the bleeding thing pushed me over to psoriasis as well. Oops.
temmy  the distribution of the other lesions, forearm, face, ear, scalp..is not characteristic for psoriasis.
hyperfukus  the scalp and ear are actually very common for psoriasis IRL the key is more of the fact that its in areas with UV exposure...actually UV Therapy is found to be helpful in treating some pts w/Psoriasis. Lastly the appearance and lots of things bleed if they were trying to go for auspitz sign it would have tiny dots of bright red blood with slightly touching it
hyperfukus  oh last thing psoriasis itches! they said no itching
... cry2mucheveryday made a comment on nbme21/block1/q#26 (A 62-year-old man who is a farmer comes to the...)
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submitted by cry2mucheveryday(8)

i fell for bleeding from lesion at chose psoriasis but psoriasis pts experience itching. Also, the distribution is not characteristic.

... benzjonez made a comment on nbme21/block1/q#27 (A 60-year-old man is brought to the emergency...)
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submitted by benzjonez(11)

FA 2018 p. 609. Suspect urethral injury if blood is seen at the urethral meatus. Mechanism of posterior urethral injury = pelvic fracture, which we see in this patient. Urethral catheterization is relatively contraindicated.

hyperfukus  thank you!
... hayayah made a comment on nbme21/block1/q#28 (A 47-year-old man is brought to the emergency...)
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submitted by hayayah(377)

Mixed venous oxygen saturation (SvO2) is measured in the pulmonary artery. SvO2 samples the true mixed venous blood leaving the right heart. Measurement of mixed venous oxygen saturation (SvO2) from the pulmonary artery has been advocated as an indirect index of tissue oxygenation.

In cardiogenic shock you have decreased CO --> decreased O2 delivery --> decreased SvO2.

... nicnac20 made a comment on nbme21/block1/q#28 (A 47-year-old man is brought to the emergency...)
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submitted by nicnac20(5)

Mixed venous oxygen tension is the amount of oxygen bound to hemoglobin as it returns to the right side of the heart after traveling to the tissues.

Decreased oxygen delivery to the tissues due to decreased cardiac output leads to the tissues extracting more oxygen from the passing RBCs than they normally would, which decreases the overall mixed venous oxygen tension.

pparalpha  A helpful equation is CO=rate of O2 consumption/(arterial O2 content-venous O2 content): Fick principle If CO is decreased, then the difference between arterial O2 content and venous O2 content is increased
... kentuckyfan made a comment on nbme21/block1/q#28 (A 47-year-old man is brought to the emergency...)
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submitted by kentuckyfan(12)

I get why the mixed venous oxygen tension decreased. However,, isn't the systemic vascular resistance also decreased?

yb_26  no, decreased CO => peripheral vasoconstriction => SVR will be increased
yssya1992  No SVR will increase due to RAAS and SAN thats why we decrease afterload in HF treatment ( ACEI, ARBs )
snafull  Wouldn't pulmonary vascular resistance also be decreased here due to pulmonary vasodilation in the setting of an MI?
cienfuegos  @snafull: my initial thought is that we would see pulmonary vasoconstriction because of the relatively low oxygen tension (that results from the low cardiac output).
... drdre made a comment on nbme21/block1/q#29 (A 34-year-old man comes to the physician because of...)
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submitted by drdre(4)

Page 506 FA 2019 describes headaches.

Cluster

  • Unilateral
  • 15 mins to 3 hours
  • Periorbital pain with lacrimation and rhinorrhea
  • Tx: Sumatriptan

Migraine

  • Unilateral
  • 4 to 72 hours
  • Pulsating pain with nausea, photophobia, phonophobia, may have "aura"
  • CN V, meninges or blood vessel irritation
  • Tx: NSAIDS, triptans, dihydroergotamine

Tension

  • Bilateral
  • 4 to 6 hours
  • Band-like pain
  • Tx: analgesics, NSAIDS, acetaminophen

drdre  yay formatting fail
drdoom  @drdre, next time try hitting enter twice ("start a new paragraph") before beginning a list.
temmy  cluster mostly seen in men
... sinforslide made a comment on nbme21/block1/q#30 (A newborn has female external genitalia and a 46,XY...)
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submitted by sinforslide(8)

Male internal genitalia -> Intact SRY , testes, and testosterone.

No female internal genitalia -> Presence of MIF (antimullerian hormone) and intact Sertoli cell function.

Female external genitalia -> No androgen present, which is required for male external genitalia formation.

d_holles  Not sure I understand why T is wrong, but DHT is correct.
d_holles  I thought about this some more -- DHT forms external genitalia while T forms 'male genital ducts'. That's why the correct answer is DHT, not T, since the PT had +ext genitalia, but -internal genitalia. I was thinking that the PT had CAIS, but that would lead to testes only w/o male genital ducts. See FA2019 p608.
d_holles  *I meant -ext genitalia, +int genitalia
... mcl made a comment on nbme21/block1/q#30 (A newborn has female external genitalia and a 46,XY...)
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submitted by mcl(186)

Per p608 in FA 2019, SRY on Y chromosome results in development of testes. DHT results in development of male external genitalia (and the prostate).

mrsmac  No sertoli cells or lack of mullerian inhibitory factor makes more sense. bc there is both male and female internal genitalia but only male external genatalia. and karyotype would show 46XY. First Aid 2018 pg. 604 - the "Sexual Differentiation" charge delineates exactly this. If it were 5areductase deficiency the child would have testicles and scrotum, which in this case is absence. Hope this makes sense. Please let me know if you disagree and why. Thanks.
mixmasta  I believe the tricky part is that they don't mention the status of the Male external genitalia. Pg. 605 from FA ( bottom portion) shows the external development of the Male/Female genitalia; you see DHT is need for male. Furthermore, pg. 604 (SEXUAL DIFFERENTIATION) DHT is also needed for Male external development.
niboonsh  My understanding of this is that the diagnosis is 5alpha reductase deficiency because the newborn has female external (aka ambiguous) with male internal (aka "male genital ducts"). According to FA, leydig cells produce testosterone, which can either stimulate the mesonephric duct to form the INTERNAL male genitals (as see in the pt). Testosterone can also be acted on by 5alpha reductase to become Dihydrotestosterone, which forms the male EXTERNAL genitalia. Since this kid has "female" genitals, but has male insides and is 46XY, id say this is a simple case of 5alpha reductase deficiency. No sertoli cells or no MIF would present as both female and male internal (because MIF typically inhibits differentiation of female internal) and male external genitalia (bcuz leydig cells are unaffected)
... yo made a comment on nbme21/block1/q#30 (A newborn has female external genitalia and a 46,XY...)
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Dang this question threw me off because it said female genitalia when I thought it would be ambiguous at birth. DHT still makes the most sense. Thanks.

... et-tu-bromocriptine made a comment on nbme21/block1/q#30 (A newborn has female external genitalia and a 46,XY...)
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submitted by et-tu-bromocriptine(14)

Everything has been covered already, but here's to the visual learners - it's easy to see the relationship between DHT and testosterone. https://imgur.com/a/M8Y3Fdm

(ignore the whole black versus blue colors...it complicates things and I'm sure I miscolored somewhere).

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